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E. M. JOHNSON.

SPARK PLUG. Armcmou mso nulu. Isla.

Patentedh Oct. 14, 1919.

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L'. MJohnson .UNITED lvstln'risfe PATENT @wenn n. Jonsson. or vmanine11mm, n.

Beitknown that I, Eowann Jamison, a citizenoflthef-United States, residing at .To 'Inkom it may conccm.' i

'Blytheville, in the county"of-Mississ1ppi and State of Arkansas, have invented cer-4 tain new and' useful Improvements in Spark-Plugs, of which the follovvin isla ',speciication, reference being had to t 1e accom anying drawings. T lis invention relates ments in sparkplugs, and it is an obJect of 4the inventlon to rovide a. novel and imi proved device ov se l which fis constructed an `assembled in a this neral character manner to eliminate substantially all possibility of breakage. A

It is also an object of the invention to [thereof is materially prolonged.`

- wherein the f ss4 An additional 'object of the'invention is to provide a novel and improved spark rimary-electrode is dis or shell'iand eective inthrough a' bo ther with means sulated there rom `to whereby the electrode 1s held e inst dis` i placement under the influence o ancxplo- @The invention consists'in fthe detais of construction and in the combination'- and arrangement of the several parte' of my im, proved 'spark plug whereby' certain important advantages are attained and the device rendered simplen-:less expensive and otherwise more convenient and advantageous for v' as will hereinafter more fully` set p The novel' features of my invention willi l "held n ninst .disphu'ement-funder the infill*V be the will now proceed to de#` hereinafter be definitely' claimed. f

I n order that mvfinventlon may' better understeod l scribethe samewith reference to the accom- "As disclosed inthe accom anyng drewvF1511 ngitudinal sectional view ings B'- denotes 'a body or s nell formed of rconductive materiel, and Apreferably brass,f,

to certain improve-A v duced portion 5 ofthe bore 4, v n f f l.Also threaded upon f l1e' 'electrode 'gnd threaded neat 1 wherebysthe devloeln'aly be: proper! `appliedin working- Apoe 1,313,450, Qspwxnpauan b zfrert'ierirstm.- wI-atentedtibti l vapplesauce inea Janurysmelo.; seala-avanti'.

section so that the` same may i.

vwith a suitable tool ior'eitherapplying'' 'removing the plug.v .A 1

The body' or shellB has axially g therethrough it bore 4 havi, '-a-.portio'n' 5 Y reduced at av point substantie y its nter and extending; throu h -i the ,bore .4jis laA prim-ary electrode 6. 'hreade'dnpon .end portion of the electrode 6- is. elongated slt-eve 7 of insulntin materlind the comsnugly fitting within't e restricted ensure- .itioned udjgnt the inner. and that i "vlhrtd Slw'' V'f is amemberprfnuc stoff. .adiameter substantially. the.s9.v|ne as"thljY diameter of 'the 'sleeve .7 andinte be.-

"we i,

tween 'the member or nut 8f andj he .inner u' 'vnd of thcsleeve 7 is nn insulating Washer.'

9 of u diameter substantially 'equal .t0 Vthe dinnieter of timbers-4; The opposite portion of the 'electrode has alsothreaded thereupon a second sleeve 7'-o insulating materia] and which hesite-inner end abuttingitlle member lor n'nt 8 and its outer end'- terminating a slight distance: inwardly. ofA

the tiring cud of the body or shell-B(v i' between the washer 9 and-the adjacent an# A t Surrounding the .vdeever '7 nnd'intcrposedl nnlar should 10 as uiorded by `the reduced 1 l ort-ion 5 of the bore 4 is n sleeve 1'14 also of'- msulnting nmteriul. Bythis means it v villv be 'seen that the electrode 6 'is effectively cnvv o mi explosion.' j Y lhol sleeve 7 1n advanceofthe Washer 9 is also surrounded snhlting nmterul, am

its inner end portion extending over "the nag-.mhur or nut 8 und -contacting with ,thel

washer 9 that the sleeve' 12 nlso serves 5 to eli'evtivcly insulatotl'lc m'ember o'r fmt 8,1

whichs preferably formed of'mutal soJthat 1' thev same will have the desired resistance. VThe sleeve V12 Vter:,l'inntes inwnrdl of the firing end nl ,the bore 4, and inward y of the outer end of the sleeve 7 and thedwull-of said bore outwurdly of the sleeve 12 has in threaded engagement therewith a bushing 14 of insulating material and which bushin r abuts the outer end of the sleeve 12 an snugly enge es the edjacent end portion of the sleeve 7 The bushing 14 also extends a slight distance beyond the adjacent or fir' ing end of the body or shell B. The electrede 6 terminates outwardly of the bushing 14 as is clearly illustrated in Fig. 1. The bushing 14 serves to eectuall close the workin end of the bore 4 so t at fouling of the e ectrode 6 and particularly resulting from corrosion of the body or shell B is eliminated.

The opposite or outer end portion of the electrode 6 and the sleeve flextends exteriorly of the body or shell B and surrounding the sleeve 7 is a bushing 15 also of insulating material which is threaded within the adjacent end portion of the bore 4. Threaded upon the bushingr 15 is a binding member or nut 16 which contacts with the adjacent end of the body or shell B and serves to effectuallv lock the bushing 15 in desired position.

t is preferred that the ,outer end of the bushing 15 be substantially ush with the outer end of the sleeve 7 so that the binding Washer 17 and nut 18 may be properly engaged with the extended portion oi the electrede 6, so that said electrode may oe propbe seen that there w erly connected with's source of electricai energy.

The electrode 6 between the inner end of the bushing 15 and the reduced portion 5 of the bore 4 of the body or shell B is surrounded by an cir space a in communication with the atmosphere through the ports 19 'formed in the body or sheil B and preferably diametrically opposed. B'y this it will 1l be e constant iiow of air through Athe ports 1.9 und the space a. This f low of air serves to effectuallyfcool the electrode 6 whereby the life of the electrode is materially prolonged.

The workin or firing end of the body B at one side of t e bore 4 is provided with a.4

- socket 20 in which is threaded an end ortion of the secondary Velectrode 21 w ich eoacts with the firing or working end 6 in a. well known manner.

In applying the electrode 6 the same is inserted through the body or shell B from the working or firing end thereof, and for which reason the electrode 21 must of necessity be rotated in order to ermit this insertion.. It is aiso to be un erstood that the electrode 6 is removed from the same end of the body or sheil B. In removing the electrode 6, it is also to bc understood that it is only necessary that the washer 17 and nut 18 be removed, and also the bushing 14,

From the foregoing description` it is thought to 'he gbvious that a spark plug which it may be assembled and operated, en d y it will also be obvious that my invention 1s susceptible of some change and modification without departingv from the princi les and spirit thereof and for this reason do not wish to be understood as limiting myself to the precise arrangement formation of the several parts herein shown in carrying out my invention in practice except as here; inafter claimed.

I claim: A

1. A spark plug comprising-a shell hliving a bore extending therethrough, "an intermediate portion of the bore being restricted, an electrode extendingthrough the bore, an

insulating sleeve surrounding' said electrode and snugly fittinp;l within the restricted por'- tion of the bore, s member threaded upon the'electrode andV positioned adjacent the inner end of the sleeve, an insulating washer interposed between the member and the inner end of the sleeve, and a second sleeve'interposed between the washer and the adjacent shoulder aiorded by the reduced *pori-- tion of the bore, and a second electrode enwith the shell and enacting witlithe first electrode. l

2., A spark plug comprising arshell `hav-` ing a-borelextending therethrough, an intermediate portion of the bore being restricted,

sleeve interposed between the washer andthe adjacent shoulder aiiorded bythe red duced portion of the bore, s second electrode engaged with Athe hell and coacting with the first electrode, and a bushin of insuletF4 ing4 material extending within e firing end portion of the bore of the body and en ing over one of the Vfirst named sleeves an terminating beyond* the firing end 'ofV the shell. i

3. A spark plug comprisin a shellhaving( a bore extending therethroug an ntenne'dithe member and j iuv.

ate portion of the bore beinpr'estrirteian electrode extending through the bore, spaced insulating sleeves ,surrounding said elec tronic, one of-said sleeves snugly fitting within the portion of the bore, a. member threaded upon' the electrode and posi.-

toned between the sleeves, an insulating.

washer interposed 4ln'etvvcen the member and' the inner end of one of the sleeves, sleeve interposed between the washer and the adjacent shoulder ulforded by the reva third g duoed portion of the bore, a second electrode the opposite end portion -of the bore and engaged with the shell and enacting with the surrounding the first named sleeve. 10 first electrode, and a bushing of insulating 1n testimony whereof I hereuntd alix my material extending within the firing end signature in the resence of two witnesses.

5 portion of the bore of the body end engag- E WARD M. JOHNSON.

my. over one of the first named sleeves and Witnesses: terminating beyondV the firing end of the W. E. LAWSON, shell, and a second bushing threaded Within ROBERT A. Boswm.

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